The polymerization and copolymerization of methylmethacrylate with a chiral organolanthanide catalysts, such as Cp'.sub.2 LnR (Cp'=C.sub.5 Me.sub.5, R=CH.sub.3 or H and Ln=Sm, Y, Lu) yields a substantially syndiotactic polymethyl methacrylate. (H. Yasuda, et al, J. Am. Chem. Soc. 1992, 114, 4908-4910.) However, catalyst improvements would be of great practical importance if better control over stereoregularities from syndiotacticities to isotacticities could be obtained, the use of undesired excess of co-catalysts were eliminated, and molecular weight and molecular weight distribution could be controlled, and the isospecific polymer nature could be easily prepared and controlled.
As such, there is a need to control stereochemistry in a great many chemicals and polymers and chiral metal catalysts offer an efficient means to do this. The design of a chiral metal catalyst necessarily relies on the design of appropriate ligands which create an asymmetric environment about the metal center. Certain classes of organolanthanide catalysts which are highly active for a variety of reactive purposes are known and described in U.S. Pat. Nos. 4,668,773 and 4,801,666. Organolanthanide hydrides, (Cp'.sub.2 LnH).sub.2 and (Me.sub.2 SiCp".sub.2 LnH).sub.2, (Cp'=.eta..sub.5 -(CH.sub.3).sub.5 C.sub.5, Cp"=.eta..sub.5 -(CH.sub.3).sub.4 C.sub.5 are known to effectively and selectively catalyze a number of olefin transformations including hydrogenation, oligomerization/polymerization, and hydroamination. Heretofore it has not been known whether an appropriate coordination environment could be devised to effect lanthanide-centered asymmetric catalytic transformation and to obtain favorable characteristics, such as extremely rapid kinetics, large turnover capacity, and reactivity tunable with the specific chiral ligand used. The synthesis of stereoregular polymers has been reported with the use of chiral organs-group IV (Ti, Zr, Hf) catalysts having approximate C.sub.2 symmetry. Such catalysts resulted in isospecific polymerization of .alpha.-olefins. Most of the ligands for these "C.sub.2 " catalysts are based upon indenyl or related cyclopentadienyl components, and are difficult and expensive to synthesize. In only a few cases are the isotacticities of the polymeric products at a useful level.